Craniosynostosis affects the majority of mucopolysaccharidosis patients and can contribute to increased intracranial pressure

Mucopolysaccharidosis type II B complicated by optic disc swelling, pigmentary retinopathy and macular edema

PURPOSE

To report clinical and imaging features of optic nerve and retinal involvement in a patient with mucopolysaccharidosis (MPS) type II B.

METHODS

A 27-year-old man, diagnosed with MPS type II B and undergoing enzymatic substitution therapy for the past 19 years, was referred to the retina service. An ophthalmological evaluation, which included multimodal imaging, was conducted to investigate potential retinal and optic disc involvement.

RESULTS

The eye examination revealed a pigmentary retinopathy with a predominant loss of the outer retinal loss, primarily in the parafoveal and perifoveal regions. Notably, multimodal imaging identified macular edema without any signs of leakage, implying an association between macular edema and retinal neurodegeneration. Additionally, both eyes exhibited an optic disc with blurred margins.

CONCLUSION

We herein describe the multimodal imaging findings of retinal and optic disc involvement in a patient with MPS type II B. This report describes for the first-time the presence of macular edema without leakage alongside photoreceptor damage and optic disc swelling.

Posterior Fossa Horns in Hurler Syndrome: Prevalence and Regression

Posterior fossa "horns" caused by internal hypertrophy of the occipitomastoid sutures are one of the more recently defined cranial abnormalities described in mucopolysaccharidoses, especially in Hurler Syndrome. However, details of this finding, including the development and natural history, are not well-understood. Two hundred eighty-six brain MR imaging studies of 61 patients with mucopolysaccharidosis I-Hurler syndrome treated at single institution between 1996 and 2015 were studied. Posterior fossa horn height was measured as the perpendicular distance from the tip of the horn to the expected curvature of the occipital inner table. Fifty-seven of the 61 patients (93.4%) had evidence of posterior fossa horns on at least one occasion. The initial average height of the right horn was 4.5 mm, and the left horn, 4.7 mm. Most of the posterior horns regressed before transplantation in our cohort, though the exact age was variable among the patients. Nearly all patients in our cohort had posterior fossa horns, and these horns regressed with age. The regression of the horns frequently started before transplantation. This trend has not been previously described, and it may suggest unknown effects of mucopolysaccharidosis on skull development.

Sickle Cell Disease Association with Premature Suture Fusion in Young Children

Sickle cell disease (SCD) leads to the formation of an atypical hemoglobin tetramer with reduced capacity to carry oxygen. Although correlation between SCD and craniosynostosis (CS) has been mentioned, these are mostly small series or case reports. This article aimed to study any correlation between these entities in a large pediatric population.

Methods

We retrospectively reviewed head CT scans of SCD patients from 0 to 8 years of age who required a CT for issues unrelated to their head shape between 2012 and 2020. We excluded patients with known history of CS or any CS-related syndrome, hydrocephalus, shunt placement, history of cranial surgery, or any reported cerebral or cranial shape abnormality.

Results

Ninety-four CT scans were analyzed. The mean age at imaging was 4.48 ± 2.30 years. CS prevalence in this cohort was 19.1%. Analysis between independent variables and patients with +CS showed that SCD-associated vasculopathy, first-degree relatives with SCD, and the use of folic acid had a statistically significant association with CS development.

Conclusions

Approximately 20% of pediatric patients with SCD developed CS. This association was higher in those patients who had a family history of SCD, used folic acid, and had SCD-associated vasculopathy. While the clinical impact of these findings needs more extensive study, centers that manage patients with SCD should be aware of the relatively high concordance of these diagnoses, vigilantly monitor head shape and growth parameters, and understand the potential risks associated with unidentified or untreated CS.

Cephalocranial Disproportionate Fossa Volume and Normal Skull Base Angle in Pfeiffer Syndrome

BACKGROUND

Pfeiffer syndrome is a rare syndromic craniosynostosis disorder, with a wide range of clinical manifestations. This study aims to investigate the structural abnormalities of cranial fossa and skull base development in Pfeiffer patients, to provide an anatomic basis for surgical interventions.

METHOD

Thirty preoperative CT scans of Pfeiffer syndrome patients were compared to 35 normal controls. Subgroup comparisons, related to differing suture synostosis, were performed.

RESULTS

Overall, the volume of anterior and middle cranial fossae in Pfeiffer patients were increased by 31% (P < 0.001) and 19% (P = 0.004), versus controls. Volume of the posterior fossa in Pfeiffer patients was reduced by 14% (P = 0.026). When only associated with bicoronal synostosis, Pfeiffer syndrome patients developed enlarged anterior (68%, P = 0.001) and middle (40%, P = 0.031) fossae. However, sagittal synostosis cases only developed an enlarged anterior fossa (47%, P < 0.001). The patients with solely bilateral squamosal synostosis, developed simultaneous reduced anterior, middle and posterior cranial fossae volume (all P ≤ 0.002). The overall skull base angulation, measured on both intracranial and subcranial surfaces, grew normally.

CONCLUSION

Enlarged anterior cranial fossae in Pfeiffer syndrome children is evident, except for the squamosal synostosis cases which developed reduced volume in all fossae. Volume of the middle cranial fossa is influenced by associated cranial vault suture synostosis, specifically, sagittal synostosis cases develop normal middle fossa volume, while the bicoronal cases develop increased middle fossa volume. Posterior cranial fossa development is restricted by shortened posterior cranial base length. Surgical intervention in Pfeiffer syndrome patients optimally should be indexed to different suture synostosis.

Hip disease in Mucopolysaccharidoses and Mucolipidoses: A review of mechanisms, interventions and future perspectives

The hips are frequently involved in inheritable diseases which affect the bones. The clinical and radiological presentation of these diseases may be very similar to common hip disorders as developmental dysplasia of the hip, osteoarthritis and avascular necrosis, so the diagnosis may be easily overlooked and treatment may be suboptimal. Mucopolysaccharidosis (MPS) and Mucolipidosis (ML II and III) are lysosomal storage disorders with multisystemic involvement. Characteristic skeletal abnormalities, known as dysostosis multiplex, are common in MPS and ML and originate from intra-lysosomal storage of glycosaminoglycans in cells of the cartilage, bones and ligaments. The hip joint is severely affected in MPS and ML. Hip pathology results in limitations in mobility and pain from young age, and negatively affects quality of life. In order to better understand the underlying process that causes hip disease in MPS and ML, this review first describes the normal physiological (embryonic) hip joint development, including the interplay between the acetabulum and the femoral head. In the second part the factors contributing to altered hip morphology and function in MPS and ML are discussed, such as abnormal development of the pelvic- and femoral bones (which results in altered biomechanical forces) and inflammation. In the last part of this review therapeutic options and future perspectives are addressed.

Posterior fossa horns; a new calvarial finding of mucopolysaccharidoses with well-known cranial MRI features

Background/aim

Mucopolysaccharidoses (MPS) are a group of hereditary metabolic diseases. The aim of this study was to share the previously unreported calvarial finding of internal hypertrophy of the occipitomastoid sutures (IHOMS) together with some other well-known cranial MRI findings in this patient series.

Materials and methods

A retrospective evaluation was conducted of 80 cranial MRIs of patients who had been diagnosed and followed up with MPS from 2008 to 2019 in our center. Of these patients, 11 had Hurler, 14 had Hunter, 24 had Sanfilippo, 15 had Morquio, 14 had Maroteaux–Lamy, and 2 had Sly disease. The cranial MRIs were assessed in two main groups as parenchymal intradural cranial MRI findings and extradural calvarial findings.

Results

The most common parenchymal intradural cranial MRI findings were white matter signal alterations (n = 51, 63%) and perivascular space enlargements (n = 39, 48%). The most common extradural calvarial findings were J-shaped sella (n = 45, 56%) and tympanic effusion (n = 44, 55%). Although IHOMS was defined in a relatively small number of the patients (n = 12, 15%), the prevalence rate was high in MPS type I (n = 6, 54%).

Conclusion

The abnormal cranial MRI findings of the MPS patients, including the newly identified IHOMS, may provide diagnostic clues to differentiate the type of the disease in radiological imaging.

Craniosynostosis and metabolic bone disorder. A review

INTRODUCTION

Some metabolic bone disorders may result in the premature closure of one or more calvarial sutures during childhood, potentially leading to a cranioencephalic disproportion. The aim of this paper is to review the characteristics and consequences of craniosynostosis associated with metabolic disorder.

MATERIAL AND METHODS

A review of the literature on metabolic forms of craniosynostosis was performed.

RESULTS

The most common forms of craniosynostosis associated with metabolic bone disorder were isolated sagittal suture fusion with or without scaphocephaly, and sagittal suture fusion associated with coronal suture fusion (oxycephaly) or also with lambdoid suture fusion (pansynostosis). Synostosis may be well-tolerated, but in some subjects results in neurodevelopmental and functional impairment that is sometimes severe.

CONCLUSION

The impact of metabolic synostosis is very variable, depending on the specific underlying metabolic disease, with a large spectrum of morphological and functional consequences. Diagnosis should be early and management should be carried out by a multidisciplinary team with expertise in both rare skeletal disorders and craniosynostosis. The impact of emergent medical therapies recently developed for some of these diseases will be assessed by systematic coherent follow-up of international registries.